1. Field of the Invention
The present invention is directed to a method for three-dimensional imaging of a moving examination subject, particularly heart imaging with an examination apparatus having at least one C-arm with a radiation source and a radiation receiver.
2. Description of the Prior Art
A standard application for an examination apparatus or angiography system of the C-arm type is the registration of projection images from one or from a few different directions. Usually, the exposures are produced as two-dimensional projection images and are viewed as such. Three-dimensional reconstructions of the examination region for presenting a three-dimensional angiography image are used only in interventional imaging for treating diseases of the vascular system in the brain on the basis of the two-dimensional projection images that have been registered. The known possibilities, however, only allow the examination and three-dimensional presentation of examination regions from which adequate data has been obtained. It would be desirable in heart imaging to be able to produce three-dimensional presentations of the heart in different phases in order, in particular to be able to investigate the coronary vessels in this way. This is currently not possible, however, because too few projection images for the same heart phase can be registered with the examination apparatus within the extremely short time during which the added contrast agent required for the registration of the projection image is located in the examination region. The usual contrast agent dwell time in the examination region, i.e. for example the coronary vessels, amounts to only approximately two seconds. Given a standard rotational speed of the C-arm of 20°/s and assumed pulse of 60, i.e. a heart frequency of 1 Hz, this means that only two projections from different angles can be obtained at the same heart phase and are available for the 3D reconstruction. Thus no diagnostic three-dimensional presentation can be reconstructed.